Contact-making voltmeter.



F. H. WINTER.

CONTACT MAKING VOLTMETER.

APPLICATION FILED mum. I. an.

1 ,267, 1 56. Patented May 2i, 1918.

Inventor F'red H.Winter-,

His Attorney.

.gizcd, are supplied with energy from the UNITED STATES PATENT OFFICE.

SCHENECTADY, YORK, ASSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATIONOF NEW YORK.

FRED H. WINTER, OF

UONTACT-MAKING VOLTHETIB.

Patented May 21, 1918.

' Application one larch i, 1917. Serial a... 151,111.

will differ from that in the feeders or that said voltages will be outof s nchronism. In contact voltmeters of the kin under consideration, itis customary and practically necessary to locate the holding means andthe winding which actuates the movable contact member close to oneanother. It therefore results that the magnetic field of one overla sthe magnetic field of the other. In case t e voltage of the controlcircuits has the same frequency as, and is in synchronism with, thevoltage of the feeders, the magnetic interference is of little moment,since this diiference may be taken into consideration in designin thevarious windings. If, however the v0 tage of the control circuits has adi erent frequency than the voltage of the feeder the ma neticinterference ecomes troublesome since it results in a fluctuation, aboveand below the desired value, in the holding effect of saidelectromagnetic holding means. If the voltage of the supcircuits is outof synchronism with, but the volta e of the 1 ,26'7' 156, Specificationof Letterii Patent.

To all whom it may concern:

Be it known that I, FRED H. Wm'rnn, a citizen of the United States,residin at Schenectady, county of Schenectady, tate of New York, haveinvented certain new an useful Improvements in Contact-MakingVoltmeters, of which the following is a specification.

My invention relates to contact making meters, and more especially tocontact making voltnieters in which electromagnetic holding means areemployed to prevent chattering of the contacts.

In the use of motor driven feeder regulators of the induction type, theoperation of the motor is controlled by means of a special form ofcontrol device commonly known as a contact making voltmeter. Variationsin voltage on the feeders cause the voltmeter to close one or the otherof two circuits and thereby eflcct the rotation of the motor, and henceof the movable element of the inductionregulator, in one direction orthe other ply so as to restone the feeder voltage to the dehas the samefrequency as,

sired value. When the movable contact feeder the' holding effect ofsaidrelectromember of the voltmeter engages one of the magn ic holdingmeans is less than when stationary contacts in response to a change thet volitages are in synchronism.

in feeder voltage, it is desired that such conlt the o ject of myinvention to protact be maintained until a i certain apprevide means inaicontact making meter of the the difficulciable correction has beeneffected in the type above referred wliereby feeder voltage in ordertoprevent objecti'onties, heretofore aneti w th when the controlablechatterin of said contacts. To this end ling circuits are, supplied wlthenergy rom a source other titan that to which the feeders are connected,are avoided;

Although my invention is useful in any relation where a evice is underthe joint control of clectroinagnetic means connected to separatealternating current sources, nevit has hereto ore 13 en proposed toemploy electromagnetic hoiding means which become effective upon theengagement of the movable contact member with a stationary contactmember to hold the former in engagement with the latter until apredeter:

mined'change in the feeder voltage is eifectertheless, in theaccompanying drawing cd. Where the control circuits, y which I haveelected to illustrate my invention as applied to a contact makingvoltmeter which is adapted to,control the operation of feeder regulatorof the induction type.

In said drawing, Figure 1 is a diagrammatic view showing the essentialarts of my contact making voltmeter, toget er with connections adaptingthe same to the control of an induction regulator, and Fig. 2 is". viewof a modification showing a different arrangement of the windings of thecontact making voltmeter.

Referring to Fig. 1, the feeder 1 is shown as connected to an inductionrezgulator 2 of the usual type, which is adapte to be opermcan thecircuits through which the control of the motor is effected and fromwhich the electromagnetic holding means are enersame source as thefeeder circuit, the voltage of. which is to be regulated, thearrangement to \vhich'brief reference has been made operatessatisfactorily. In some installations, however, it is desirable tosupply the said control circuits from a source of energy olhcr than thatfrom which the feeder circoils are supplied, and in this event it ispossible and quite probable that the frequency of the voltage in thesupply circuits ated by a motor 3. The motor is controlled by thecontact making voltmeter 4 which comprises stationary cont cts 5 and 6,a movable contact member 7 a apted to coiiperate with said stationarycontact, and a movable core ,8, attached to said movable contact memberand :adapted to be actuated blya a winding 9, which is connected througa variable resistance 10 to the secondary of a potential transformer 11,the primary of which is connected to .the feeder 1. p

The contact making voltmeter is also provided with the electromagnets 12and 13, which are adapted, when the movable contact member 7 engageswith the stationary contacts 5 and 6 respectively, to hold said movablecontact member in engagement therewith. The winding of the electromagnet12 is connected to the stationary contact 5 and, through a resistance14, to one phase 15 of a three-phase circuit. The windin of theelectromagnet 13 is connected throng a winding 16, which cooperates withthe movable core, 8 to the stationary contact 6 and, through aresistance 17, to another phase 18 of said three-phase circuit. Themovable contact member 7 is connected to a third phase 19 of saidthree-phase circuit. The winding 16 and the winding of the electroma net13 are wound oppositely with respect to t e flux developed by winding9.

A low voltage relay 20, the winding of which is connected across thesecondary of the transformer 11, is adapted, upon a suflicient reductionin the feeder voltage, to disengage the movable contact member 21, whichis electrically connected to stationary contact 5, from the stationarycontact 22, with which it normally engages and cause it to engage withstationary contact 23.

The motor 3, which may be a three-phase induction motor, is suppliedwith energy from the phases 15, 18 and 19 of a threephase circuit, theconnections of the first two of which to the motor are ada )ted to bereversed by the switch 24 and t e connection of the last one of which tothe motors is permanent. adapted, to be operated by the electromagnets25 and 26. which have movable cores connected to said switch. Uponreversing the connections of the phases 15 and '16 to the inductionmotor 3 a reversal in the di rection of rotation of said motor results.

One terminal of the winding of the electromagnet 25 is connected bothto, the stationary contact 6 and to the stationary contact 23. whereasthe other terminal is connected to the phase 18. "One terminal of thewinding-of the electromagnet 26 is con nected to the stationary contact22, whereas theother terminal is connected to the phase 15.

The contact making voltmeter, illustrated in Fig. 2, is in most respectslike that illus- The reversing switch 24 is trated in Fig. 1, asisjnd'ciited by, the use of like ref rence num rs i clicatecorresponding elements in t e two figures, except that the auxiliarywinding 16 and the winding of electromagnet 13ers adapted to beconnected in parallel, r ther than in series, upon the engagement oimovable contact 7 with contact 6. y

The operation of the system, to which my invention is applied, isunderstood to be as follows: Upon the feeder voltage decreasing belowthe desired value, the'movable contact member 7 will be caused to engagewith stationary contact 5 whereupon parallel'circuits are established,one of which extends from the movable contact member 7, which is, aspreviously indicated, permanently connected to the phase 19, through thewinding of the electromagnet 12 and the resistance 14 to the base 15,and the other of which extends rom the movable contact member 7 throughthe movable con tact member 21, stationary contact 22 and the winding ofthe electromagnet 26 to the phase 15. The electromagnets 12 and 26 aretherefore simultaneously energized. the former exerting a holding effectupon the movable contact member 7, and the latter effecting the movementof the switch 21 to the right-hand position thereof, whereupon arotation of the motor 3 in a direction to increase the feeder voltageresults.

In a similar manner, if the feeder; voltage is above the predeterminedvalue, the movable contact member 7 will be caused to engage with thestationary contact 6 whereupon two circuits are established, one ofwhich extends from the movable contact member 7 through winding 16 andthe winding of the electromagnet 13, connected in series, in case thearrangement illustrated in Fig. 1 obtains, or in mult' ]e in case thearrangement illustrated in l ig. 2 obtains, and the resistance 17 to thephase 18, and the other of which ex en s from said movable contact 7through the winding of electromagnet 25 to the phase18. Theelectromagnets 13 and 25 are therefore simultaneously energized, the.former exertinga holding effect upon the movable contact member 7 andthelatter effecting the movement of the switch 24 to the left-handposition thereof. whereupon a rotation of the motor 3 in a direction todecrease the feeder voltage results.

' lVith special reference to the function of my invention which involvesthe use of the winding 16, let it be assumed that the mow its ablecontact 7 is in engagement with contact ployed, the flux ormagnetomotive force developed by the winding 9 will alternately cause anincrease or decrease in the holding eifeet of electromagnet 13,'sincethe electromagnet 13 is located within the magnetic field set up by saidwinding 9. If the voltage in the control circuits be out of synchronismwith that of the feeder, but have the same frequency, the holding effectof the electromagnet 13 will be less than when said voltages are insynchronism. To compensate for the variations in the holding effect ofelectromag et 13, the winding 16 is employed. This winding 16, accordingto the drawing, is located adjacent the winding 9 and is woundoppositely, with respect to the flux developed by winding 9, to thewinding of eleetromagnet 13. If the magnetolnotive force of winding 9 bein a direction to oppose that of the winding of the electromagnet 13,which may be assumed to be the condition when the voltages impressedupon said windings are 180 degrees out of phase, the magnetomotive forceof winding 16 will be in the same direction as that of winding 9 andhence the force tending to lift the core 8 will be increased by anamount sufficient to compensate for the decreased holding efi'ect ofelectromagnet 13. Similarly if the magnetomotive force of winding 9 bein a direction to assist that of the winding of the electromagnet 13,which may be assumed to be the condition when the voltages impressedupon the said windings are in phase, the magnetomotive force of winding16 will oppose that of winding 9 and hence the force tending to lift thecore 8 will be decreased, by reason of such opposition, by an amountsufficient to compensate for the increased holding efiect of theelectromagnet 13. Furthermore in the modification illustrated in Fig. 1,in which the windings 16 and the winding of'electromagnet 13 are inseries, the electromotive forces induced in said windings will opposeeach other by reason of the fact that, as previously mentioned. saidwindings are oppositely wound with respect to the flux set up bv thewinding 9 and hence the circuit including the winding of electromagnet13 is rendered non-inductive, to any desired degree, with respect to thewinding 9.

The magnetic field set up by winding 9 also produces an effect on thewindin of the eleclromagnet 12, but this is not objectionable since thewinding of elcctromagnet 12 and winding 9 are so related to each otherand to the movable member 7 that when the holding effect ofelectromagnet 12 is weakened there is a reciprocal action tending toweaken the effect of winding 9, and when the holding efiect ofelectromagnet 12 is increased the effect of winding 9 likewiseincreases.

A low voltage relay 20, which operates,

upon an abnormal decrease in the feeder voltage, to electrically connectthe stationary contact 5 with the stationary contact 23 and hence toenergize the electromagnet 25 to move the switch 24 into the positionillustrated and thus to cause a rotation of the induction motor 3 in adirection to reduce the feeder voltage, is provided to prevent anadjustment of the regulator to decrease the feeder voltage upon anabnormal decrease thereof.

I conceive that various modifications of my invention may be made and Iaccordingly do not desire to be limited to the exact arrangement shown,but seek to cover in the apended claims all such modifications andarrangements as fall within the scope and spirit of my invention.

\Vhat I claim as new and desire to secure by Letters Patent of theUnited States, is,

1. In an alternating current contact making meter, the combination of astationary contact, a movable contact adapted to cooperate therewith,electro-responsive means vfor actuating said movable contact, awindingadapted to be ener 'zed upon the engagement of said movab econtact with said stat onary contact and tending, when energized, tomaintain such enga ement, and

means adapted to compensate or the magnetic interference between saidelectro-responsive means and said winding.

2. In an alternating current contact making meter, the combination of astationary contact, a movable contact adapted to cooperate therewith,electro-responsive means for actuating said movable contact, and aplurality of windings adapted to be ener gized upon the engagement ofsaid movable contact with said stationary contact, one of said windingstending, when energized, to maintain the en agement between said movablecontact an said stationary contact and another of said windings tending,when energized, to compensate for the magnetic interference between saidelectro-responsive means and the first mentioned winding.

3. In an alternating current contact making meter, the combination of aplurality of stationary contacts, a movable contact adapted to cooperatetherewith, electro-responsive means for efi'ecting the operation of saidmovable contact, a winding adapted to be energized upon the engagementof said movable contact with one of said stationary contacts andtending, when energized. to maintain such engagement, and a plurality ofwindings adapted to be energized upon the engagement of said movablecontact with another of said stationarv contacts, one of said lastmentioned windings tending, when ener ized, to maintain engagement between sai movable contact and said last mentioned stationary contact andthe other of said windings tending, when energized,

'to compensate for the magnetic interference between saidelectro-responsive means and the other of the last mentioned windings.

4. The combination with a plurality of alternating current circuits of acontact making meter comprising a stationary contact, a movable contactadapted to cotiperate therewith, electro-responsive means, responsive toan electrical condition in one of said circuits, for efi'ecting theoperation of said movable contact, a winding cooperatin with saidelectro-responsive means and a apted to be energized for another of saidcircuits upon the enga ement of said movable contact with sai stationarycontact, and electromagnetic means adapted to be energized from the lastmentioned circuit upon the engagement of said .movable contact with saidstationary contact and tending, when energized, to maintain suchengagement, said winding and said electro-magnetic means being sorelated as to compensate for the magnetic interference between saidelectroresponsive means and said winding.

5. The combination with a plurality of alternating current circuits of acontact making meter comprising a stationary contact, a movable contactadapted to cooperate therewith, electro-responsive means, responsive toan electrical condition in one-of said circuits, for effecting theoperation of said movable contact, a winding coiiperatin with saidelectro-responsive means and ad apted to be energized from another ofsaid circuits upon the engagement of said movable con tact with saldstationary contact, and electromagnetic means comprising awindingadapted to be energized from the last men-- tioned circuit upon theengagement of said movable contact with said stationary contact andtending, when energized, to maintain such engagement, said windings beinoppositely wound with respect to the di ction of the magnetic fielddeveloped by said electro-responsive means.

6. The combination with a plurality of alternating current circuits of acontact making meter comprising a stationary contact, a movable contactadapted to coiiperate therewith, electro-responsive means, responsive toan electrical condition in one of said circuits, for actuating saidmovable contact, a lurality of windings oppositely wound Will! respectto the direction of the magnetic field developed by saidelectroresponsive means and adapted to be serially connected to anotherof said circuits upon the engagement of said movable contact with saidstationary contact, one of said windings tending, when so connected, tomaintain engagement between said movable contact and said stationarycontact and another of said windings coiiperating with and adapted tomodify the action of said electroresponsive means.

7. The combination with a feeder circuit I and an induction typeregulator therefor, of a reversible motor for adjusting the position ofthe movable element of said regulator and thereby adjusting the voltageon said feeder circuit, an alternating current suppl circuit for saidmotor independent of said eeder circuit, electromagnetic reversing meansfor said motor, and a contact making voltmeter adapted to control saidelectromagnetic reversing means, said contact making tact with t e firstmentioned stationary contact and tending, when so connected, to maintainsuch engagement, and a plurality of windings oppositely wound withrespect to the direction of the magnetic field set up by saidelectio-responsive means and adapted to be serially connected to saidindependent alternating current supply circuit upon the engagement ofsaid movable contact with the second mentioned stationary contact, oneof said windings tending, when so connected, to maintain engagementbetween said movable contact and the second mentioned stationary contactand the other of said windings cooperating with and adapted to modifythe action of said electroonsive means,

8. The combination with feeder circuit and an induction type re tortherefor, of a reversible motor for a j iisting the positlon of themovable element of said regulator and thereby adjusting the voltage onsaid feeder circuit, an alternatin current supply circuit for said motorin ependent of s a1d feeder circuit, electromagnetic reversing means forsaid motor, a contact making voltmeter adapted to control saidelectromagnetic reversing means, said contact making voltmetercomprising stationary contacts, a movable contact adapted tocooperatetherewith, electro-responsive means, responsive to a decreasein feeder volta c, for eflecting the engagement of said mova le contactwith one 0 said stationa contacts and, to an increase in feeder vo tage,for efi'ectmg the engagement of said movable contact w th another ofsaid stationary contacts, a winding adapted to be connected to saidindependent alternating current sup ly circuit upon the engagement ofsaid movable contact with the first mentioned stationary morgue ofwindings oppositely wound with respect to the direction of the magneticfield set up by said electro-responsive means and adapted to be seriallyconnected to said independent alternating current supply circuit uponthe engagement of said movable contact with the second mentionedstationary contact, one of said windings tending, when so connected, tomaintain engagement between said movable contact and the secondmentioned stationary contact and the other of said windings cooperatingwith and adapted to modify theaction of said electro-responsive meansand means operative upon an abnormal decrease in the Voltage of saidfeeder circuit for causing said motor to adjust the regulator for aminimum feeder voltage.

In witness whereof, I have hereunto set my hand this 28th day ofFebruary, 1917.

FRED H. WINTER.

